DID YOU KNOW? Clint Eastwood was never anyone’s first choice to play Dirty Harry. The character was written in his late 50s in the original script, and Frank Sinatra was cast and accepted the role. But as rewrites and directors came and went, so did Sinatra. Eastwood is 41 years old when the film is finally offered to him. The killer in this film is based on the real-life Zodiac Killer, who had committed five murders in the San Francisco Bay Area several years earlier. The role of the killer is